Colour has the potential to influence people’s emotions and behaviour. However, there is little empirical research exploring in depth how colour influences performance. This study focuses on exploring the impact of colour on two particular responses: impulsivity and arousal. Response time and error rate were used as two indicators to define the levels of impulsivity and arousal. The impact of colour on impulsivity, arousal, and emotions were investigated in detail. To achieve this goal, three psychophysical experiments were conducted to explore the impact of hue and chroma on impulsivity and arousal; and how colour influences impulsivity, arousal and colour emotions such as colour heat. The hue and chroma experiments were designed to determine whether, in a particular colour environment, response time and error rate of the participants were different across different hues and chroma levels. Participants were required to complete a range of screen-based psychometric tests with different colour backgrounds. During the experiment, participants were asked to give their responses to each test as quickly and accurately as possible. The results showed that background hue and chroma differences significantly influence response time and error rate. This suggests that colour has a distinctive influence on impulsivity and arousal. Hue has a greater influence on arousal than impulsivity while chroma affect impulsivity more than arousal. The impact of colour on impulsivity and arousal were also considered with different psychometric test types, different genders and colour preference. To explore the impact of colour on impulsivity, arousal and emotions, the emotion experiment was designed to study ten emotion scales. Participants were asked to report their emotional responses to 20 colours both on cardboard and textile fabric based on ten emotion scales. The reliability of Ou’s (2004) colour emotion models for single colour have been verified using the experimental data in this study. This result suggested that colour influence on impulsivity and arousal can be linked with other emotions. The finding from this study can be applied in various affective design, such as product packaging, consumer purchasing, education efficiency and so forth.